Hot top for ingot molds



Sept. 29, 1931. M, G, UMAS 1,825,446

HOT TOP FOR INGOT MOLDS F iled Au 25, 1950 INVENTOR Patented Sept. 29,1931 MAXWELL GERSON DUMAS, OF PITTSBURGH,

PENNSYLVANIA HOT TOP FOR INGOT MOLDS Application filed August 23, 1930.Serial No. 477,269.

This invention relates to hot tops for ingot molds and it is among theobjects thereof to provide a form of hot top or feeder which shall beadapted to provide a pressure column of maximum height in a minimum massof metal to be fed to the ingot.

In the pouring of ingots provision is made to provide, an excess'mass ofmolten metal which is fed into the ingot while the metal is setting orcooling to prevent forming of pipe, so-called, and to obtain an ingot ofmore nearly uniform density throughout.

After the ingot is formed, the excess metal is cropped off or sheared,such sheared off portion being commonly referred to as croppage whichconstitutes the waste metal or scrap which is an expensive item in themanufacture of ingot steel.

It is among the objects of the present in vention to produce a miximumhead of pressure in the metalto be fed to the ingot and at the same timereduce the croppage to a minimum and to accomplish this object provisionis made to prevent freezing to render the full force of the pressureeffective to densify the top portion of the ingot metal.

These and other objects will become more apparent from a considerationof the accom- Jan in drawin s in which like reference charactersdesignate like parts and in which Fig. 1 is a vertical sectional view ofone form of hot top embodying the principles of this invention; Fig. 2 avertical sectional elevational view illustrating the feedingposition ofa hot top onan ingot mold; and Fig. 3 a top plan view of the hot topshown in Fig. 2.

With reference to Figs. 1 to 3 inclusive of the drawings, 1 generallydesignates an ingot mold, 2 a hot top which is provided with oifsetportions or shoulders 3 in the form of a peripheral flange which engagesthe top of the mold 1 to rest the hot top thereon. The particular mannerof supporting the hot top forms no part of this invention as the hot topmay be supported on top of the ingot mold in any convenient and suitablemanner.

The hot top 2 is designated to provide a volume of metal of such massthat it will re-' tain its molten condition for a sufiicient period tocomplete the feeding of the metal into the ingot mold, this being thedetermining factor in hot top designs.

In accordance with the present invention, the hot top 2 is formed of amaximum height and formed to have its inner walls 4 of convex shape asshown. in Figs. 1 and 2, thereby producing a maximum height or columnwhich determines the head pressure of the molten metal in the feeder.The minimum diameter of the interior of the hot top should besufficiently great to prevent freezing of the metal and in any eventshould not be less than one-half of the diameter of the lower opening 5of the hot top, this having been determined as a safe proportion on thebasis that the greater mass below the minimum cross-sectional area ofthe hot top retains the heat to the extent that the metal does notfreeze very rapidly at its most constricted portion. For the same reasonthe increasing diameter at the top of the hot top assists in preventingthe freezing of the metal at the constricted portion, thus establishingthat the convex shape of the inner walls is very effective andconsistent with the maintenance of the maximum head pressure for feedingpurposes.

The tops of hot tops shown in Fig. 1 is reversible so that either endmay be supported on the ingot mold; however, it may. be desirous to formsupporting shoulders as illustrated in the hot top of Big. 2.

In Fig. 1, the outer walls of the hot top are straight and the innerWalls convex to produce a maximum thickness of wall section at theminimum section of the metal, thus further reducing freezing in thethroat portion by reducing heat loss by radiation at this portion.

Although a round shape of hot top is illustrated in Fig. 3 of thedrawings, in practice the ingot molds are ordinarily of oblong,rectangular, or fluted shape and the exterior of the hot top is usuallyshaped to conform to the shape of the mold.

From the foregoing description it will be apparent that a maximum headpressure is obtainable with a minimum mass of metal to be fed by sodistorting the mass that it will lot produce a maximum height withoutconstricting any portion thereof, to the extent of causing too rapidfreezing when the metal is setting.

5 I claim herein as my invention:

1. A hot top structure for feeding metal to ingots comprising a hollowbody having its longitudinal wall section of substantiallyconvexo-concave shape to produce a maximum columnar pressure in a givenmass'of molten metal.

2. .A hot top structure for feedingmetal to ingots comprising a hollowbody having its longitudinal inner surface of substantially convex shapewith its minimum diameter at the mid-portion and gradually increasing indiameter toward the respective ends thereof.

In testimony whereof I have hereunto set my hand.

MAXWELL'GERSON DUMAS.

